1. Field of The Invention
The invention relates to a method of and an apparatus for manufacturing semiconductors, in which a thin film for semiconductors is formed by particularly using a liquid raw material and a liquefied raw material obtained by liquefying a liquid raw material in manufacturing semiconductors.
2. Description of The Related Art
A conventional method of manufacturing a thin film for semiconductors includes a method of using a liquid raw material to spray the same under vacuum, applying the sprayed liquid to a substrate, heating the substrate to volatilize a volatile solvent in the liquid applied to the substrate to form a thin film. Japanese Patent Unexamined Publication No. 6-306181 discloses, as an embodiment of the conventional method, a method of and an apparatus for manufacturing an organic optical thin film.
FIG. 6 is a schematic view showing an apparatus disclosed in the publication described above.
In FIG. 6, a vacuum chamber 5 is exhausted and evacuated by a vacuum exhausting unit 6. A wafer 4 is held and heated on a susceptor 3. A liquid raw material, in which an organic optical thin film material or an inorganic optical thin film material is dissolved in a volatile solvent, passes an opening and closing mechanism portion 301 from within a liquid raw material tank 25 to be sprayed into the vacuum chamber 5 from a control nozzle unit 300. The sprayed liquid raw material makes liquid droplets in the vacuum to reach the wafer 4, which is held and heated on the susceptor 3, as it is, and is applied onto the wafer 4.
Then, a volatile component of the liquid raw material applied onto the wafer 4 in the liquid state is volatilized by heat from the susceptor 3 and a surface heating device 306, so that a solid component is left on the wafer 4 to form a film. At this time, the solvent component volatilized by heat makes gases to be discharged to the vacuum chamber 5. A part of the discharged gas is exhausted by the vacuum exhausting unit 6, but most of the discharged gas is adsorbed by a cold trap 304, which is cooled to a low temperature, and is again condensed to make a liquid to maintain a desired vacuum.
In addition, in FIG. 6, the reference numeral 11 denotes a vacuum gauge; 302 a shutter; 303 a substrate temperature measuring device; 305 a baking device; and 310 a vacuum pump. Further, the reference numeral 311 denotes a manipulator; 312 a substrate introducing device; 320 denotes a vacuum pump; 321 a mass spectroscope; 322 denotes an ionizing device; and 323 a gate valve.
Further, as for other conventional techniques, Japanese Patent Unexamined Publication No. 9-36108 describes a method of and an apparatus for manufacturing semiconductors. Japanese Patent Unexamined Publication No. 9-36108 is directed to enhancing a vaporizing efficiency of a liquid raw material to prevent unnecessary formation of a film within an apparatus, thereby improving productivity in manufacture of semiconductors.
To attain the object described above, the present apparatus is constructed such that a liquid raw material is pressure fed by a gas for delivery of the liquid raw material to be to a vaporizing nozzle, and the vaporizing nozzle is supplied with a carrier gas and a gas raw material. With the arrangement, the liquid raw material from the vaporizing nozzle is made to collide against a carrier gas and a gas raw material to make fine droplets within in a vacuum chamber, in which a thin film is to be manufactured, and is efficiently vaporized to form a thin film on the wafer.
Hereupon, it is possible to enhance productivity in semiconductors in a method of manufacturing semiconductors, if a gas required for film formation, for example, oxygen can be uniformly supplied to a wafer, and so kinds of films capable of film formation can be extended to films which can be formed by a liquid raw material and the above-described gas, in addition to films which can be formed only by a liquid raw material.
However, with the conventional technique described in Japanese Patent Unexamined Publication No. 6-306181 described above, there is not disclosed any means for uniformly supplying a gas required for film formation to a wafer within a vacuum chamber. Accordingly, at the time of heating a liquid raw material to deposit a thin film, it is not possible to supply the gas required for the film forming reaction to the wafer placed on a susceptor.
In the conventional technique described above, if a gas is required for the film forming reaction, a separate pipe, through which a necessary gas is supplied, must be connected to the vacuum chamber.
However, even with such arrangement, there is the need of a gas dispersing plate, a shower head and the like for uniformly supplying the gas to the wafer placed on the susceptor. As a result, films, which can be formed in such arrangement, will be greatly limited in terms of kind, so that the arrangement is made limitative in use to make it difficult to enhance productivity.
Thus, as described in Japanese Patent Unexamined Publication No. 9-36108, it is contemplated to supply a liquid raw material to a vaporizing nozzle together with a carrier gas and a gas raw material.
However, the technique described in Japanese Patent Unexamined Publication No. 9-36108 is directed to enhancing a vaporizing efficiency of a liquid raw material, and so provides an arrangement, in which a gas is positively made to collide against a liquid before the liquid is sprayed to the vacuum chamber.
When the liquid is positively made to collide against the gas, a difference in mass between droplets and the gas greatly varies the distribution of the gas, so that the gas required for film formation cannot be uniformly supplied to a wafer.
Further, when the gas is positively made to collide against the liquid before the liquid is sprayed in the vacuum chamber, the gas is in some cases promoted in dissolving into the liquid. When spraying the liquid, in which the gas is dissolved in large amount in the vacuum, bubbles are formed in large amount since the gas contained in the liquid tends to violently move into gas phase. These bubbles sometimes prevent the liquid and the gas from being supplied into the vacuum chamber, so that the gas required for film formation cannot be uniformly supplied to a wafer.
An object of the invention is to realize a method of manufacturing semiconductors and an apparatus for manufacturing semiconductors, in which a liquid raw material can be uniformly supplied to a wafer and a gas required for film formation can be uniformly supplied to a wafer.
In order to achieve the object described above, the invention is structured in the following manner.
(1) In a method of manufacturing a semiconductor, there are provided a step of making at least a part of a liquid raw material for a thin film to be formed on a substrate of a semiconductor fine droplets in a space in which the thin film is formed, and supplying the fine droplets to the substrate from a liquid raw material spray port, and a step of supplying a gas required for forming the thin film to the substrate from a gas supply port formed in a periphery of the liquid raw material spray port.
(2) Preferably, in the method described in the item (1) described above, the gas supply port is arranged at the same interval with respect to the substrate as the liquid raw material spray port, or is arranged in an upstream side of a side for supplying the liquid raw material in comparison with the liquid raw material spray port.
(3) Further, preferably, in the method described in the item (1) described above, the thin film is formed while the gas is intermittently supplied to the substrate.
(4) Further, preferably, in the method described in the item (1) described above, the thin film is formed by using a chemical vapor deposition reaction.
(5) Further, preferably, in the method described in the item (1) described above, the liquid raw material is obtained by liquefying a solid or dissolving the solid into a solvent.
(6) Further, in an apparatus for manufacturing a semiconductor, there are provided with vaporizing means which makes at least a part of a liquid raw material for a thin film to be formed on a substrate of a semiconductor fine droplets in a space in which the thin film is formed and has a liquid raw material droplet port for supplying the fine droplets to the substrate, and a gas supply pipe having a gas supply port which is formed in a periphery of the liquid raw material spray port and supplies a gas required for forming the thin film to the substrate.
(7) Preferably, in the apparatus described in the item (6) described above, the gas supply port is arranged at the same distance with respect to the substrate as the liquid raw material spray port, or is arranged in an upstream side of a side for supplying the liquid raw material in comparison with the liquid raw material spray port.
When the supply port for supplying the gas required for the thin film forming reaction is provided in the periphery of the liquid raw material spray port, it is possible supply the gas so that the gas is uniformly supplied on the surface of the substrate without preventing the liquid raw material from being sprayed.